/**
@page pbe_example_code PBE example code
	
	This example covers: 
		-# @ref pbe_example_1 "Encrypting some data with a password and writing it to a file"
		-# @ref pbe_example_2 "Reading the data back from the file and decrypting it with the same password".

	<i>This example code is really for reference only - it would be better to use:</i>
		- @ref secure_stream_example_code
		- @ref secure_store_example_code	

<hr>

	- @ref pbe_example_code_support "Supporting code for this example".

@anchor pbe_example_1
@code
/*
 * Encrypt data with password and write it to a file.
 */
void CPBEExample::WriteEncryptedDataL(const TDesC8& aInput, const TDesC& aFilename, const TDesC& aPassword)
		 {
		 // Open a stream to the output file
		 RFileWriteStream writeStream;
		 User::LeaveIfError(writeStream.Replace(iFs, aFilename, EFileShareExclusive | EFileWrite));
		 CleanupClosePushL(writeStream);

		 // Create a CPBEncryptElement object, passing details of the encryption we
		 // are using and the user's password
		 CPBEncryptElement* encryption = CPBEncryptElement::NewLC(aPassword, ECipherDES_CBC);

		 // This is used to create a CPBEncryptor object
		 CPBEncryptor* encryptor = encryption->NewEncryptLC();

		 // Create a buffer of appropriate size to hold the ciphertext
		 HBufC8* ciphertextTemp = HBufC8::NewLC(encryptor->MaxFinalOutputLength(aInput.Length()));
		 TPtr8 ciphertext = ciphertextTemp->Des();		 

		 // Encrypt the input data into the ciphertext buffer
		 encryptor->ProcessFinalL(aInput, ciphertext);

		 // Store encryption data.  This contains details of the encryption used (e.g.,
		 // cipher, key size) as well as things like the salt.  This must be stored
		 // along with the encrypted data, otherwise it is not possible to decrypt it
		 // again!
		 writeStream << encryption->EncryptionData();

		 // Store the ciphertext
		 writeStream << ciphertext;

		 // Commit the stream
		 writeStream.CommitL();

		 // Free memory (writeStream, encryption, encryptor, ciphertextTemp)
		 CleanupStack::PopAndDestroy(4, &writeStream);
		 }
@endcode

@anchor pbe_example_2
@code
/*
 * Read data from file and decrypt it.
 */
HBufC8* CPBEExample::ReadEncryptedDataLC(const TDesC& aFilename, const TDesC& aPassword)
		 {
		 // Open a stream to the input file
		 RFileReadStream readStream;
		 User::LeaveIfError(readStream.Open(iFs, aFilename, EFileRead));
		 CleanupClosePushL(readStream);

		 // Read the encryption data from the file
		 CPBEncryptionData* encryptionData = CPBEncryptionData::NewLC(readStream);
		 
		 // Recreate the CPBEncryptElement object, using the encryption data from the
		 // file and the user's password.  This will leave with KErrBadPassphrase if
		 // the password is wrong.
		 CPBEncryptElement* encryption = CPBEncryptElement::NewLC(*encryptionData, aPassword);

		 // This is used to create a CPBDecryptor object
		 CPBDecryptor* decryptor = encryption->NewDecryptLC();
		 
		 // Read the ciphertext
		 HBufC8* ciphertext = HBufC8::NewLC(readStream, KMaxTInt);

		 // Allocate a buffer for the plaintext (this will be returned to the caller)
		 HBufC8* plaintextBuf = HBufC8::NewLC(decryptor->MaxFinalOutputLength(ciphertext->Length()));
		 TPtr8 plaintext = plaintextBuf->Des();

		 // Decrypt the data
		 decryptor->ProcessFinalL(*ciphertext, plaintext);

		 // Free memory (readStream, encryptionData, encryption, decryptor, ciphertext, plaintext)
		 CleanupStack::Pop(plaintextBuf); // don't free this
		 CleanupStack::PopAndDestroy(5, &readStream);
		 CleanupStack::PushL(plaintextBuf);

		 // Return plaintext to the caller
		 return plaintextBuf;
		 }

@endcode

*/